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TO ALL WHOM IT MAY CON CERN:

Be it known that I, ROBERT H. LECKY, of the city and county of Allegheny, in the State 'of Pennsylvania., have invented a :lowland useful Improvement in Lathe-Dog 3 and I do hereby declare that the following is afull and exact description thereof, reference being had to the accompanying drawings, and tothe letters of reference marked thereon.

The nature of my invention consists in providing a lathe-dog with a tongue or cam, constructed, arranged,

-and operating in the manner and for the purpose hereinafter described.

To enable others skilled in the art to make and use my` invention, I will proceed to describe its construction und operation. l

In the accompanying drawings, which form part of my specification- Figure l is a face view of my improved lathe-dog, representing the tongue or cam thrown back for the purpose of inserting the end of Vthe article tov be turned. I

Figure 2 is a face view of the same, representing the opening partiallycloscd by the tongue or cam. Figure Sis a side view of the tongue or cam. v In the drawings, A represents the bodyV of the lathe-dog, which is provided with an opening, C. In the side of the body an opening is made for receiving the tongue-or cam B. The opening or cavity made in the body A should fit close to the sides ofthe tongue or cam, and that part ofthe cavity in which that portion ofthe tongue or cam marked D is pivoted, should be made to lift very exact, so as to form a hinged knuckle or socket-joint, so that all strain on or against the tongue or cam will be on the circular part D, and the pin e, which holds the tongue or cam to its place, relieved from all strain or force brought to bear on Vor against the body ofthe tongue or cam. In one side of the tongue or cam ie a curved groove marked :v Thecentre from which the lines of this curved groove are drawn, isthe centre of' the pivot-opening o. This groove xgradually increases in depth from tne'point n to the'poi'nt :r, so' as to form a curved inclined plane. In the side of the bodyA is placed a thumbscrcw,f, so arranged that its point will enter the grootte :e of the tongue or cam. e represents the pivot-pin or screw, which passes through'tbe' opening o of the tongue or cam. The griping-edge ofthe tongue or cam should be provided with iine teeth or corrugaticns, so that it will readilygrasp the article placed in the opening C.

From the foregoing description, and by reference to the accompanying drawings, the skilful mechanic will i readily understand theconstruction of my improved lathe-dog," and the relation that the diierent parts bear to cach other. willrtherefore proceed to describe the operation of my improvement.V

Having all things constructed and arranged as herein described and represented, I then throw baclrlthe tongue or cem B, as shown in tig. 1. I then piace one end of the article to be turned in the opening C, and then press the tongue or cam B against the article placed in the opening C. The article isthen placed in the turning-lathe'in the ordinary manner. The tongue or cam4 B will increase itsgrasp on the article in proportion to the increase of pressure brought against the leg it of the body A. The thumb-screw `fis used f-'or holding the tongue or cam in a fixed position, which will be necessary in eases requiring a reverse motion oi' the lathe in the turning process.

' The inclined'groove :c will causethe thumb-screivf toincrease its hold on the tongue or cam by any back movement of it. y

The advantages of my improvement consist in adapting a single 1athe-dog to the various diameters of the different articles to be held in a fixed position in the turning-lathe.

Having thus described thenature, construction, and operation ofmy improvement, what-I claim as of my imvention, is.-

The body A, cam B, thumb-screwf, and groove x, constructed, arranged, and operating substantially as herein described and for thepurpose set forth.

a. H. LEcKY.

Witnesses:

A. C. JOHNSTON, JAMES J., JoHNs'roN. 

